Abstract
Bovine mastitis is a multi-aetiological ailment that accounts for the immense economic losses due to fall in milk production and poor quality of milk as well as therapeutic expenditures. Bovine protothecal mastitis is caused by Prototheca zopfii and P. wickerhamii and has been reported in most of the countries of the world. Dirty environment and lack of hygiene in herd play a vital role in transmission of the malady. Faeces from infected cows transmit the organisms into environment. Age, stage of lactation, host's immune status and previous exposure to treatment as well as other ailments predispose the animal to the disease. Multiplication of the organisms in the mammary gland and regional lymph node results in damage of mammary parenchyma leading to fall in milk yield and, sometimes, drying of infected quarters. Organisms infrequently disseminate from the site of lesion to visceral organs. Though intense inflammatory reaction is not seen in protothecal mastitis, still induration, fibrotic hard udder, fall in milk yield with presence of clots in milk and increase in somatic cell count are commonly associated with algal mastitis. Diagnosis is usually accomplished by selective isolation and light microscopic demonstration of the organism, which can be further aided by carbohydrate and alcohol assimilation test, fluorescence microscopy, fine needle aspiration associated with electron microscopy or detection of antibodies by counter-flow electrophoresis. Poor sensitivity of the organism to the conventional antibiotics limits their use in treatment. Antifungals like nystatin, amphotericin, polymyxin, miconazole as well as levamisole tetramisole proved beneficial to some extent. Eradication of the pathogen from herd is a difficult and practically an impossible task, leaving only preventive measures as the resort for controlling the disease.